We usually think of solar, or photovoltaic (PV), cells fixed to roofs, converting sunlight into electricity, but bringing that technology indoors could further boost the energy efficiency of buildings and energize swaths of wireless smart technologies such as smoke alarms, cameras and temperature sensors , also called Internet of Things (IoT) devices. Now, a study from the National Institute of Standards and Technology (NIST) suggests that a straightforward approach for capturing light indoors may be within reach.